The present invention relates to devices for controlling flow of hydraulic fluid such as engine lubricant to the valve lifters or lash adjusters in a multi-cylinder internal combustion engine. Devices of this type may be employed for deactivating combustion chamber valves of selected cylinders in the engine during light load operation for the purposes of minimizing engine fuel consumption.
In engines having an air throttle, it has been found that air flow restriction or throttling losses during light load operation with the throttle nearly closed increase the rate of fuel consumption; whereas, operation of the engine at near fully open throttle minimize the air throttling losses and improves the fuel economy of the engine. Accordingly, it has been desired to operate the throttled engine under conditions in which the throttle is opened a greater amount for given engine load conditions. This may be accomplished by deactivating the combustion chamber valves of selected cylinders and running the engine on fewer cylinders, therefore requiring greater throttle opening to maintain the engine power while operating on the fewer cylinders. Thus, it has been desired to employ engine cylinder deactivation to improve the fuel economy of large multi-cylinder engines and yet provide the desired power output of the engine when operating with all cylinders firing.
Heretofore, the technique most commonly employed for selectively deactivating the combustion chamber valves has utilized electrically operated valves for controlling the flow of engine lubricant to the lash adjusters or lifters of the valves for the cylinders selected for deactivation. In particular, the electrically operated valves have been mounted on a gasket secured to a deckplate having a supply channel providing pressurized engine lubricant to each of the valves; and, each valve is mounted on the gasket to control flow to selected outlet ports in communication with the individual lash adjuster/valve lifter control ports provided on the deckplate.
Such electro-hydraulic assemblies have been known as Lifter Oil Manifold Assemblies (LOMA) in the art of engine combustion chamber valve deactivation for multi-cylinder engines, particularly those employed having a V-type configuration for use in passenger cars and light trucks.
The assembly of the valves and the gasket has been retained on the deckplate by a superimposed rigid metal plate for stiffening the gasket assembly, with a mounting bracket superimposed thereover and which retains the valves in position in the valving chambers. The assembly may then be attached to the engine block by through bolts for mounting the deckplate over the appropriate lash adjuster/lifter galleries on the engine.
One example of a known system for the aforesaid type electro-hydraulic manifold assembly for cylinder combustion chamber valve deactivation is that shown and described in U.S. Pat. No. 6,644,265.
Referring to FIGS. 2 and 4, another known configuration of a LOMA is illustrated wherein the deckplate 1 has a supply channel 2 formed therein on one side or face and a plurality of individual output channels 3, 4, 5, 6 spaced thereon for communicating with lifter oil gallery ports (not shown) on one cylinder bank of a V-8 engine. The deckplate 2 is typically formed of metal such as aluminum. It will be understood that the assembly is illustrated in the inverted position in FIG. 4, with respect to the installed position on an engine.
A gasket assembly 7 has a flexible elastomeric seal bead 8 provided on the upper surface; and a corresponding flexible seal (not shown) provided on the undersurface for sealing against the deckplate 1. Gasket 7 has a plurality of valve mounting bosses 9, 10, 11, 12 extending upwardly therefrom and formed integrally with gasket 7. The bosses 9 through 12 each include an inlet port (not shown) which communicates with the supply channel 2 and an outlet port (not shown) which communicates respectively with one of the channels 3, 4, 5, 6 on the deckplate; and, accordingly the valve bosses 9–12 are located on the gasket 7 so as to have the outlet of each boss communicate respectively with one of the channels 3–6. A rigid stiffening plate commonly formed of metal denoted by reference numeral 13 is received over the gasket for insuring sealing, the gasket over the deckplate and for resisting deflection or bending and the attendant leakage caused by the forces of the pressurized oil in the channels.
Electrically operated valves 14, 15, 16, 17 are provided; and, each is received respectively in one of the bosses 9–12 with the inlet of the valve communicating with the inlet in the boss and the outlet of the valve communicating with the outlet port in the boss respectively. A retaining bracket 18 is received over the valves and plate 13 and is secured thereon by through bolts (not shown) for attachment to the engine cylinder block. Bracket 19 has a pair of lugs 20 provided thereon respectively for each of the valves 14–17 to retain the valve on the boss. A common electrical lead frame indicated generally at 21 is received over the valves to make electrical connection therewith.
The assemblies of the prior art thus have been complex and comprised of a multiplicity of pieces including a separate stiffening plate requiring individual fabricating operations and which have added weight and have been relatively costly for high volume motor vehicle engine production. Accordingly, it has long been desired to provide a way or means for providing a LOMA for engine cylinder valve deactivation which is simple, relatively low in manufacturing costs and easy to assemble on the engine.